What is the effect of ethanol concentration on bread flavor?

Therefore, does changing the yeast's ethanol production affect the bacteria which produce lactic and acetic acid, whereby influencing bread flavor?

  • The source I cite in this answer suggests that some breads can contain alcohol in measurable quantities
    – Chris H
    Commented May 24, 2021 at 8:15
  • 1
    @lerner you are conflating yeast and bacteria. Sourdough is risen by gasses given off by lactic acid producing bacteria, whereas conventional doughs are risen by yeasts. Yeasts have different flavours to bacteria. You may or may not have both yeast and bacteria in a sourdough starter and any given loaf.
    – bob1
    Commented May 24, 2021 at 9:14
  • @bob1: I'm not sure there is a misunderstanding here. The aerobic bacteria in the starter could be affected in an interesting way by an increase in ethanol concentration. But how can one vary the yeast to increase ethanol concentration? Commented May 24, 2021 at 10:22
  • @MarkWildon What I'm saying is that generally in yeast risen dough bacteria don't play a role in the flavour much, if at all, because they largely aren't present at high enough numbers or the right types. Conversely in bacterial risen ones, yeast aren't present and ethanol isn't produced (much), by the lactic acid fermentation pathway (see pathway diagram about 1/3 way down page).
    – bob1
    Commented May 24, 2021 at 10:38
  • Thanks for the responses all. @bob1 I'm pretty sure that yeasts are what rise all breads? The link you provide shows that the lactic acid fermentation pathway doesn't give off CO2, whereas the alcohol fermentation path undergone by yeast does. I did some more research and came across this which, as is logical, suggests that bacteria don't like alcohol. Perhaps maximizing the amount of aerobic respiration (decreasing ethanol) maximizes bacteria growth, and hence the typical sourdough flavors.
    – lerner
    Commented May 24, 2021 at 23:02


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